1. Field of the Invention
The present invention relates generally to hologram lenses and is directed more particularly to a method of producing an inline hologram lens.
The invention relates also to an inline hologram lens produced by the novel method.
The invention further relates to a novel optical reproducing head using the above inline hologram lens.
2. Description of the Prior Art
Previously, there has not been proposed any satisfactory, simple method which yields an inline hologram lens with a large N.A. (numerical aperture).
Because of the lack of suitable inline hologram lenses, prior art optical reproducing heads have many drawbacks, such as their substantial mass and great production expense as well as other problems.